Peristaltic transport of hydromagnetic Jeffrey fluid with temperature-dependent viscosity and thermal conductivity

2016 ◽  
Vol 09 (02) ◽  
pp. 1650029 ◽  
Author(s):  
Q. Hussain ◽  
S. Asghar ◽  
T. Hayat ◽  
A. Alsaedi

In this paper, we investigate the effects of variable viscosity and thermal conductivity on peristaltic flow of Jeffrey fluid in an asymmetric channel. The inclined magnetic field, viscous dissipation and Joule heating are also considered. Wave frame and long wavelength approximations are made to formulate the problem. Pressure gradient, pressure drop per wavelength, velocity and temperature profiles are calculated analytically and discussed graphically. Comparison is made with the previous work for reliability.

2010 ◽  
Vol 15 (3) ◽  
pp. 257-270 ◽  
Author(s):  
M. M. M. Abdou

A numerical model is developed to study the effect of thermal radiation on unsteady boundary layer flow with temperature dependent viscosity and thermal conductivity due to a stretching sheet in porous media. The Rosseland diffusion approximation is used to describe the radiative heat flux in the energy equation. The governing equations reduced to similarity boundary layer equations using suitable transformations and then solved using the Runge–Kutta numerical integration, procedure in conjunction with shooting technique. A parametric study illustrating the influence of the radiation R, variable viscosity ε, Darcy number Da, porous media inertia coefficient γ, thermal conductivity κ and unsteady A parameters on skin friction and Nusselt number.


Author(s):  
G. N. Sekhar ◽  
G. Jayalatha

A linear stability analysis of convection in viscoelastic liquids with temperature-dependent viscosity is studied using normal modes and Galerkin method. Stationary convection is shown to be the preferred mode of instability when the ratio of strain retardation parameter to stress relaxation parameter (elasticity ratio) is greater than unity. When the ratio is less than unity the possibility of oscillatory convection is shown to arise. Oscillatory convection is studied numerically for Rivlin-Ericksen, Walters B′, Maxwell and Jeffreys liquids by considering free-free and rigid-free isothermal/adiabatic boundaries. It is found that there is a tight coupling between the Rayleigh and Marangoni numbers, with an increase in one resulting in a decrease in the other. The effect of variable viscosity parameter is shown to destabilize the system. The problem reveals the stabilizing nature of strain retardation parameter and destabilizing nature of stress relaxation parameter, on the onset of convection. The Maxwell liquids are found to be more unstable than the one subscribing to Jeffreys description whereas the Rivlin-Ericksen and Walters B′ liquids are comparatively more stable. Rigid-free adiabatic boundary combination is found to give rise to a most stable system, whereas the free isothermal free adiabatic combination gives rise to a most unstable system. The problem has applications in non-isothermal systems having viscoelastic liquids as working media.


2009 ◽  
Vol 64 (9-10) ◽  
pp. 588-596 ◽  
Author(s):  
Muhammad Y. Malik ◽  
Azad Hussain ◽  
Sohail Nadeem ◽  
Tasawar Hayat

The influence of temperature dependent viscosity on the flow of a third grade fluid between two coaxial cylinders is carried out. The heat transfer analysis is further analyzed. Homotopy analysis method is employed in finding the series solutions. The effects of pertinent parameters have been explored by plotting graphs.


Energies ◽  
2020 ◽  
Vol 13 (10) ◽  
pp. 2538 ◽  
Author(s):  
Marina Astanina ◽  
Mikhail Sheremet ◽  
U. S. Mahabaleshwar ◽  
Jitender Singh

Cooling of heat-generating elements is a challenging problem in engineering. In this article, the transient free convection of a temperature-dependent viscosity liquid inside the porous cavity with copper radiator and the heat-generating element is studied using mathematical modeling techniques. The vertical and top walls of the chamber are kept at low constant temperature, while the bottom wall is kept adiabatic. The working fluid is a heat-conducting liquid with temperature-dependent viscosity. A mathematical model is developed based on dimensionless stream function, vorticity, and temperature variables. The governing properties are the variable viscosity, geometric parameters of the radiator, and size of thermally insulated strip on vertical surfaces of the cavity. The effect of these parameters on the energy transport and circulation patterns are analyzed numerically. Based on the numerical results obtained, recommendations are given on the optimal values of the governing parameters for the effective operation of the cooling system. It is shown that the optimal number of radiator fins for the cooling system configuration under consideration is 3. In addition, the thermal insulation of the vertical walls and the increased thickness of the radiator fins have a negative effect on the operation of the cooling system.


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